Seal arrangements of this kind have a broad range of applications in practice and are long-established in shock dampers and hydraulic actuators, for example.
The service lives of these seal arrangements depend decisively on the length of the life of the seal element used.
In operational use of the seal arrangement, the seal element is often subject to high mechanical loads. Thus, pressurization of the high-pressure region of the seal arrangement or translational relative movement of the two machine parts can lead to such high mechanical loads on the seal element that it may be excessively stressed and possibly even plastically deformed in the region of contact thereof with a groove flank, arranged on the low-pressure side, of the holding groove. In the extreme case, the seal element can be extruded under the loads into the sealing gap between the two machine parts. Overall, this is disadvantageous for the sealing capacity of the seal element and can lead to complete loss of functioning of the seal element. In practice, the seal element, which can be composed, for example, of a fluororubber (FKM) or of a polytetrafluoroethylene (PTFE), which is capable of bearing higher thermal stress, must therefore be of sufficiently large dimensions to be able to adequately withstand the loads which occur during operation. However, larger dimensioning of the seal element can lead, in turn, to poorer cold shrinkage behavior of the seal element. The consequence can be a poorer friction coefficient and a poorer sealing capacity of the seal element in the low-temperature range.
It is therefore the object of the invention to develop the seal arrangement mentioned at the outset and a shock damper or hydraulic actuator provided therewith in such a way that the seal element thereof is better protected from excessive loads in operational use, thus enabling the seal element to be given smaller dimensions while maintaining the service life of the seal element unchanged and possibly also enabling it to be manufactured from a material which is less resistant to mechanical loads and has an even better friction coefficient than, for example, PTFE.